The Trials and Travails of the Infrared Multipoint
OK, I’ve been waiting to post more on the Wii multipoint for a while, but I’m been waiting to get some kind of mobile infrared light system working. If you’ve watched Johnny Lee’s video, you would get the impression that it’s a 1-2-3 easy a cake thing to do.
You would be so wrong.
So, first I tried to duplicate his infrared array. He is using 100 IR LEDs to project a flood of IR light that is then reflected back to the Wiimote screen using reflective tape.
Reflective Tape: Is not easy to find. At all. Go ahead and try it. 3M sells reflective tape, but none of the hardware stores in Salt Lake City had any. As a plus, they said they could have it on hand within two weeks.
Ebay is an option if (again) you don’t mind waiting two weeks to get something. But there are many kinds of reflective tape. Which one works best? We’ll get to that part.
Infrared Array: Johnny Lee gives no specs on his IR array, so I can’t speak to its efficacy. I built one with 96 high output IR LED’s. In addition to the LED’s (which are $2 per LED at Radio Shack and closer to 30 cents per LED at Mouser), I had to get a breadboard, batteries, a voltimiter, and some resistors.
In the end, it didn’t work. The LEDs all lit up just fine, but they didn’t output anywhere near enough light to give a healthy reflection. Was this the light or the relfective tape I was using? We’ll get to that part.
Infrared Spotlight: I initially assumed it was the light. So I got my hands on a 1,000,000 candle power IR spotlight to solve that problem. Turned it on and… nothing. The Wiimote picked up the spotlight shining on my shirt, but it wouldn’t pick up the reflection off the tape. So is this a problem with the light or with the tape?
I have no idea, but I can tell you that the tape is borderline useless with everything I’ve tried.
Maybe I’m using low power IR LED’s (1.3 volt, 100mA) or maybe I’m using the wrong kind of reflective tape (I tried both engineering grade and retroreflective daybright… whatever that means), but I have had zero success replicating Johnny Lee’s design.
My next step is going to be an attempt to mount IR LED’s directly into a pair of gloves, which is how the Cynergy demo was done. This was the solutions that I finally got that working… as you’ll see in some videos over the next couple days.